1. Field of the Invention
The present invention relates to a voice recognition device which can recognize voices of a user as words.
2. Description of Related Art
In an earlier technology, there is known a voice recognition device which recognizes the user's voices to perform the input operations of various electronic installations, such as navigation system for automobile (see Japanese Patent Application Laid-open Nos. 2000-193479 and 2000-203357).
The voice recognition device of this kind stores words (terminology) required to accomplish the above input operations of various electronic installations in advance. Note, such words will be referred to “objective recognition terms”, hereinafter. In operation, the above device collates these objective recognition terms with various words vocalized by an user actually and further detects (or calculates) the degrees of agreement between the words that the user vocalized and the objective recognition terms stored in the device. Then, by comparing the so-detected degrees of agreement with each other, the objective recognition term having the largest degree of agreement is recognized as a word that the user has vocalized. Under such a situation, since “effective” words that the user is permitted to use for the input operations of various electronic installations are limited to the above-mentioned objective recognition terms, it is necessary for the user to memorize these objective recognition terms in advance of activating the electronic installations and/or vocalize on confirmation of operation manuals for the installations.
In order to lighten the user's burden and improve the recognition rate between the user's voices and the objective recognition terms, the conventional voice recognition device employs a countermeasure where the objective recognition terms that the user is permitted to use for the input operations or the objective recognition terms that the user's input (vocalization) is expected, are displayed on a monitor in advance.
In the application of the voice recognition device on a navigation system for vehicle, however, the monitor cannot display all of the objective recognition terms (e.g. names of regions, names of stations) of the user's destination at a time because of their numerous words. Therefore, when collating numerous objective recognition terms, such as destinations, with various words vocalized by the user thereby to calculate the degrees of agreement, there are arisen problems of deteriorating a recognition ratio and also wasting time for calculating the degrees of agreement.
Meanwhile, due to the difference among individuals in terms of nature of the user's voice, the user's way of speaking, etc. and the difference in surrounding atmosphere, such as presence of noise, there is a case of impossibility to judge whether one objective recognition term agrees with the user's voice, causing a misidentification. Additionally, if the voice recognition device is unable to recognize a term (words) that the user has uttered despite that such a term is being displayed on the monitor, then a sense of incompatibility may arise in the user's mind, in comparison with a case that the same term is not displayed on the monitor.